Based on the measurement requirements of current sensor with a wide range and high accuracy, a new open-loop current sensing system design method based on the combination of soft magnetic shunt technology and giant magnetoresistance (GMR) sensor is proposed. In this paper, a soft magnetic shunt structure is used to shunt and attenuate the large magnetic field generated by the large current into a smaller magnetic field, and a high sensitivity GMR sensor is used to detect the field, to achieve the detection of small magnetic field under large current and achieve the design purpose of a wide range. The measurement results showed that the sensitivity of the open-loop current sensing system is 3.95679 mV/A and the linearity is 0.38%. The open-loop current sensing system designed in this paper has the advantages of high feasibility, low nonlinear error, and wide range, and can be applied to high-precision power metering.
